An optical laminate having a polarizing film is placed on each of both sides of a liquid crystal cell of a liquid crystal display apparatus as a representative image display apparatus, the placement being attributable to an image-forming mode of the apparatus. In recent years, as thinning of the optical laminate having a polarizing film has been desired, there has been proposed a method involving subjecting a laminate of a thermoplastic resin substrate and a polyvinyl alcohol-based resin layer (hereinafter, referred to as “PVA-based resin layer”) to in-air stretching, and then immersing the laminate in a dyeing liquid so that a thin polarizing film may be obtained (for example, Patent Literature 1). However, such method involves a problem in that optical characteristics (such as polarization degree) of the thin polarizing film to be obtained are insufficient.